1 (a)Define Insulation Resistance and derive expression for it of a Cable.

6 M

1 (b)A single core cable has its conductor diameter as 2 cm and outer diameter as 5 cm. The resistivity of conductor and insulator are 1.73 ? 10-8 ? -m and 8?1012? -m respectively. Calculate resistance of conductor and insulation for a cable of 100 meter.

6 M

2 (a)Derive an expression for Energy stored in a magnetic field.

6 M

2 (b)An iron ring of mean circum ference of 50 cm has an airgap of 2mm cut in it. It has circular cross section with area of 5 cm2. It carries a coil wound with 600 turns wound uniformly. The relative permeability of iron is 580. If the coil carries a current of 2 amp. Find the Flux in air gap.

6 M

Answer any one question from Q3 & Q4

3 (a)Derive an expression of Average value of an alternating simusoidal current.

5 (a)A circuit, consisting of resistance of 20 ? and inductance of 0.1 H in series, is connected across single phase 220V, 50Hz supply. Calculate : (1) Current drawn (2) p.f. and (3) Power consumed by ckt.

6 (a)Three coils each of 5? resistance and 6? inductive reactance are connected in Delta across 3 phase, 440V, 50Hz, A.C. Supply. Calculate current drawn p.f. of system and power consumed by circuit.

7 M

6 (b)A coil of 2? resistance and 0.01 H inductance is connected in series with a capacitor across 200V supply. What must be capacitance in order that maximum current is drawn at frequency of 50 Hz. Find also voltage across capacitance.

6 M

Answer any one question from Q7 & Q8

7 (a)State and explain kirchhoff?s laws.

8 M

7 (b)Calculate the equivalent resistance between terminals X and Y for the circuit shown in Fig, 1

5 M

8 (a)Apply Thevenin's theorem to calculate current flowing in branch A-B as shown in Fig. 2